SBIR-STTR Award

A new class of fluorescent nanocrystals offers the prospect of replacing organic dyes for many fluorescence detection and analysis schemes commercially in use. BioCrystal has developed a family of proprietary fluorescence-based detection reagents which utilize a semiconductor nanocrystal core(CdSe) encased in a semiconductor(ZnS)shell and one or more organic layers which confer water solubility, as well as reactive sites which may be used to bind molecules such as affinity ligands to the functionalized nanocrystal. They are monodisperse and resist photobleaching. The Phase I work effort will demonstrate the feasibility of the following:(1)the use of a continuous flow production technique to produce monodisperse CdSe nanocrystals (CdSeNC) of uniform size in different colors to industrial proportions;(2)the industrial scale production of water-soluble, functionalized CdSeNC, including the production and purification of avidin-labeled CdSeNC;(3)the conjugation of functionalized CdSeNC to bioreceptors, and their use for detection by FRET or aggregation testing. This work will preface the Phase II objective of developing a procedure for the detection of bio-contaminants using functionalized CdSe nanocrystals, and, in parallel, to produce a miniaturized, autonomous sensor device to perform this procedure under continuous use, or during desired periods of time. Multiplexing, constant emission, particulate structure and energy transfer are inherent characteristics which afford fluorescent CdSe nanocrystals a number of advantages over fluorochromes for use in detecting multiple bio-contaminants in sensor devices, and for a number of other commercial uses: as DNA/RNA probes in qualitative disease detection; viral genotyping; automated biological assays for high throughput screening (HTS) applications in drug discovery; fluorescence-based histological studies, including the identification of cancerous tissue, and as encoded beads in multi-dimensional micro-assay formats.

In the Phase I work BioCrystal demonstrated the feasibility of producing highly fluorescent and functionalized semiconductor nanocrystals with a narrow size distribution in a systematic and reproducible manner, and further demonstrated that the properties of these fluorescent nanocrystals are superior to the properties of conventional organic dyes currently in use in fluorescence-based assays. BioCrystal further developed a novel surface chemistry that provides protection, stabilization (against oxidation, ionic strength and buffers), aqueous solubility in a wide range of pHs, functionalization and linking ability, and dramatic fluorescence enhancement (brightness). In Phase II BioCrystal will develop and successfully demonstrate a prototype automated continuous flow process system for industrial-scale production of high quality, functionalized semiconductor nanocrystals with narrow size distribution. The Phase II effort will also emphasize continuing research on techniques that are currently being developed in our laboratories for the functionalization of the nanocrystals for biological tagging. These nanocrystals will be directly conjugated to a variety of bioreceptors (i.e., antibodies, avidin, nucleic acids, and lectins)that are commonly used in biological detection and diagnostics. These conjugated nanocrystals will be fully characterized and favorably compared in selected fluorescence-based assays with conjugates of organic fluorophores commonly used today.The Phase II effort will demonstrate BioCrystal's capability of producing industrial-scale levels of high quality, monodisperse, functionalized fluorescent semiconductor nanocrystals for broad industrial applications in research and diagnostics. This effort will further demonstrate the efficacy of these functionalized nanocrystals for use in the following: nucleic acid diagnostics; DNA and antibody microarrays; immunohistochemistry; qualitative disease detection schemes; for bio-agent detection, in either air-borne or in aqueous environments; in the many different fluorescence-based assays used for research in the life sciences and clinical medicine; and for non-medical applications in identification and authentification. Upon successful demonstration of this industrial-scale production prototype system, BioCrystal will confirm its ability to adequately address market demand for fluorescent nanocrystals in the multi-billion dollar fluorescence-based bioreagent marketplace, either directly or through large, well-entrenched bioreagent company partners. BioCrystal will further demonstrate that it can readily provide functionalized fluorescent nanocrystal conjugates to the government for multiple applications in bio-detection.

Keywords:
semiconductor nanocrystals, bio-detection, monodispersity, functionalization, fluorescence, photobleaching, continuous flow system, industrial